add parameter access to servr::server_config() from sandpaper::serve()

[zkamvar]

Unfortunately the server_config snippet above doesn't seem to work for me. For example, if we try R -e 'servr::server_config(host = "192.168.1.10", port = "5000"); sandpaper::serve()' it will still serve on 127.0.0.1 and port 4321.

😩 that's what I get for testing with just the default config. I will add an ellipses to the serve function in the next release so that you should be able to run sandaper::serve(host = "192.168.1.10", port = "5000")

For reference, this is the documentation of those options that will be available:

https://yihui.r-universe.dev/servr/doc/manual.html#server_config

Originally posted by @zkamvar in carpentries/workbench#50 (comment)